Human placental membrane (e.g. amniotic membrane) has been used for various types of reconstructive surgical procedures since the early 1900s. The membrane serves as a substrate material, more commonly referred to as a biological dressing or patch graft. Such a membrane has also been used widely for ophthalmic procedures and more recently for dental regenerative procedures, treating ulcers and as adhesion barrier. Typically, the membrane is either frozen or dried for preservation and storage until needed for surgery.
Placental tissue is typically harvested after an elective Cesarean surgery. The placenta is composed of the umbilical cord and amniotic sac. The amniotic sac, commonly referred to as the amniotic membrane, has two primary layers of tissue, amnion and chorion. Amnion tissue is the innermost layer of the amniotic sac and in direct contact with the amniotic fluid. The amniotic sac contains the amniotic fluid and protects the fetal environment. Histological evaluation indicates that the membrane layers of the amnion consist of single layer of epithelium cells, thin reticular fibers (basement membrane), a thick compact layer, and fibroblast layer. The fibrous layer of amnion (i.e., the basement membrane) contains collagen types IV, V, and VII, and cell-adhesion bio-active factors including fibronectin and laminins.